It is known to drive various automobile accessory assemblies, for example, the water pump, the generator, the fan for cooling the coolant, the power steering pump, and the compressor, by the vehicle engine. This is done by a driving pulley actuated by the engine shaft of the motor vehicle which drives an endless drive belt operating the accessory assemblies through driven pulleys.
The tensioner arms in many accessory assemblies sustain large hub loads applied to them that may adversely affect tensioner arm alignment. This is especially true for front end accessory drives that utilize “high offset” or Zed-type belt tensioner designs. The hub load in Zed-type belt tensioner can be strong enough to tilt or cock the arm off of its contact surfaces when the hub load is larger than can be countered by the main tensioner spring. Consequently, the tilting or cocking of the arm causes uneven wear (and therefore shorter useful life) of components within the tensioner that contact the arm in its tiled or cocked position, e.g., a bushing on which the arm rotates.